Liquid diffusers for irrigation systems are known to comprise a main body which is adapted to be secured to a drop line of an irrigation system and has a tubular passage with one end designed for connection to the supply line and the other end equipped with a diffuser nozzle directing a liquid jet downwards.
Furthermore, a deflector plate is placed before the nozzle, for obstructing and radially deflecting the jet, for the liquid to be uniformly distributed over the surface to be irrigated.
The plate may be mounted to the support body in either fixed or movable fashion, to be able to perform a complex motion, composed of a first rotation about its center axis and a second rotation of its center axis about a center axis of the support body.
Generally, the jet-emitting nozzle is mounted in the main body in removable fashion, for replacement thereof if the jet range has to be changed.
Here, the whole diffuser is removed from the supply pipe and then at least partially disassembled for nozzle removal and replacement.
As a result, in addition to the need of disassembling the diffuser, there will be also the need of stopping the irrigation liquid supply, which will increase dead times and require more labor and personnel.
A further drawback of these prior art arrangements is difficulty in performing ordinary maintenance, particularly when soil or dirt residues must be removed.
WO2010/005508 discloses a diffuser having a quick-change nozzle that allows replacement of the nozzle when the support body is still connected to the supply pipe, without requiring the supply to be stopped and the diffuser to be disassembled.
Nevertheless, this arrangement also has a few well-known drawbacks. Namely, the support body has a lateral seat for receiving the nozzle and for quick-locking thereof, by merely transverse motion.
As a result, for a proper sealing effect to be obtained at the connector section of the nozzle for connection with the liquid delivery passage, a special seal, generally an O-ring, has to be provided, which adds complexity to both construction and assembly of the diffuser.